Vertical bipolar battery structure

Abstract

The embodiment of the utility model provides a vertical bipolar battery structure. The vertical bipolar battery structure comprises at least two stacked vertical bipolar battery cell units, each vertical bipolar cell unit comprises an end face bipolar pole piece, at least one bipolar pole piece and a connecting bipolar pole piece, and the end face bipolar pole piece, the bipolar pole piece and the connecting bipolar pole piece are sequentially stacked; diaphragms are arranged between the end face bipolar pole pieces and the bipolar pole pieces as well as between the bipolar pole pieces and the connecting bipolar pole pieces; and the two adjacent vertical bipolar battery cell units share the connecting bipolar pole piece. According to the connection bipolar pole piece, the composite current collector is adopted, so that the connection bipolar pole piece can be used as a unipolar pole piece in two stacked adjacent vertical bipolar cell units to realize connection, and the insulation between the two adjacent vertical bipolar cell units can be ensured. The structure is simple, the sealing difficulty is greatly reduced, the cost is low, and large-scale production is easy.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and in particular relates to a vertical bipolar battery structure. Background Art

[0002] With the widespread adoption of lithium-ion batteries, the shortage of lithium resources and rising raw material prices have significantly limited their development and production, necessitating the development of low-cost secondary batteries. Sodium-ion batteries, which operate on a similar mechanism to lithium-ion batteries and boast abundant sodium resources, hold great potential as a battery system.

[0003] Bipolar batteries can achieve both high voltage and energy density in a single cell. Generally, bipolar batteries can be divided into vertical and horizontal structures. In horizontal bipolar cells, the positive and negative electrodes are coated on the left and right sides of the same current collector surface during coating. This increases the voltage by extending the electrodes parallel to the electrodes, and increases the cell capacity by stacking them in parallel perpendicular to the electrodes. Vertical bipolar cells, on the other hand, stack bipolar electrodes perpendicular to the electrodes to form a series connection to increase voltage, but struggle to meet large capacity requirements.

[0004] Patent application 2023101120387 discloses a laminated cell structure and secondary battery, which stacks a negative electrode sheet, a separator, a bipolar electrode sheet, a separator, and a positive electrode sheet to form a laminated structure. The battery voltage is increased by increasing the number of bipolar electrodes between the positive and negative electrodes, and a gel polymer electrolyte or solid electrolyte is used to avoid sealing problems. At the same time, a mirror-symmetrical structure is constructed based on the above-mentioned laminated unit, and the single-sided electrode sheet in the middle is combined into a single-polarity double-sided electrode sheet, forming a structure of a single-sided positive electrode sheet, a separator, a bipolar electrode sheet, a separator, a double-sided negative electrode sheet, a separator, a bipolar electrode sheet, a separator, and a single-sided positive electrode sheet. However, the use of gel electrolytes or solid electrolytes still needs to solve the problems of large interfacial impedance and low ionic conductivity of the electrolyte itself. Moreover, when stacking the sheets using the above stacking method, six types of sheets are required: single-sided positive sheet, single-sided negative sheet, double-sided positive sheet, double-sided negative sheet, bipolar sheet with positive electrode facing upward, and bipolar sheet with negative electrode facing upward. It is not convenient to stack the sheets automatically during batch preparation, and it is difficult to perform automated operations. Utility Model Content

[0005] The present invention provides a vertical bipolar battery structure, which aims to solve the problems of existing vertical battery structures, such as small capacity, large interface impedance, low ionic conductivity of the electrolyte itself, and inconvenience in automatic lamination.

[0006] To achieve the above-mentioned purpose, an embodiment of the present invention provides a vertical bipolar battery structure, comprising at least two stacked vertical bipolar battery cell units; each of the vertical bipolar battery cell units comprises an end bipolar pole piece, at least one bipolar pole piece and a connecting bipolar pole piece, the end bipolar pole piece, the bipolar pole piece and the connecting bipolar pole piece are stacked in sequence, and a diaphragm is provided between the end bipolar pole piece and the bipolar pole piece, and between the bipolar pole piece and the connecting bipolar pole piece; two adjacent vertical bipolar battery cell units share the connecting bipolar pole piece.

[0007] As a preferred embodiment, two adjacent vertical bipolar battery cell units are connected in parallel; in the same vertical bipolar battery cell unit, the end face bipolar pole piece, the bipolar pole piece and the connecting bipolar pole piece are sequentially connected in series.

[0008] As a preferred embodiment, the end bipolar pole piece and the connecting bipolar pole piece have the same structure and size.

[0009] As a preferred embodiment, the end face bipolar pole piece includes a first composite current collector, a first positive electrode coating arranged on one side of the first composite current collector, and a first negative electrode coating arranged on the other side of the first composite current collector; the area of ​​the first negative electrode coating is larger than the area of ​​the first positive electrode coating, and the center of the first negative electrode coating overlaps with the center of the first positive electrode coating.

[0010] As a preferred embodiment, the first composite current collector includes a first insulating material, a first current collector arranged on one side of the first insulating material, and a second current collector arranged on the other side of the first insulating material; in a direction perpendicular to the first insulating material, the first current collector and the second current collector are staggered; the first negative electrode coating is arranged on the side of the first current collector away from the first insulating material; the first positive electrode coating is arranged on the side of the second current collector away from the first insulating material.

[0011] As a preferred embodiment, the connected bipolar pole piece includes a second composite current collector, a second positive electrode coating arranged on one side of the second composite current collector, and a second negative electrode coating arranged on the other side of the second composite current collector; the area of ​​the second negative electrode coating is larger than the area of ​​the second positive electrode coating, and the center of the second negative electrode coating overlaps with the center of the second positive electrode coating.

[0012] As a preferred embodiment, the second composite current collector includes a second insulating material, a third current collector arranged on one side of the second insulating material, and a fourth current collector arranged on the other side of the second insulating material; in a direction perpendicular to the second insulating material, the third current collector and the fourth current collector are staggered; the second negative electrode coating is arranged on the side of the third current collector away from the second insulating material; the second positive electrode coating is arranged on the side of the fourth current collector away from the second insulating material.

[0013] As a preferred embodiment, the bipolar pole piece includes a fifth current collector, a third positive electrode coating arranged on one side of the fifth current collector, and a third negative electrode coating arranged on the other side of the fifth current collector; the area of ​​the third negative electrode coating is larger than the area of ​​the third positive electrode coating, and the center of the third negative electrode coating is overlapped with the center of the third positive electrode coating.

[0014] As a preferred embodiment, the first negative electrode coating, the second negative electrode coating and the third negative electrode coating have the same area; the first positive electrode coating, the second positive electrode coating and the third positive electrode coating have the same area.

[0015] As a preferred embodiment, a sealing insulating layer is provided between the first current collector and the diaphragm, between the second current collector and the diaphragm, between the third current collector and the diaphragm, between the fourth current collector and the diaphragm, and between the fifth current collector and the diaphragm.

[0016] In a preferred embodiment, the first, second, and third negative electrode coatings are all disposed in contact with the corresponding sealing insulating layer; and gaps are provided between the first, second, and third positive electrode coatings and the corresponding sealing insulating layer. In this application, the sealing insulating layer is typically secured with a point-type hot melt adhesive to facilitate subsequent lamination and sealing.

[0017] The connecting bipolar pole pieces of the present application adopt a composite current collector, which can be used as a single polarity pole piece in two adjacent stacked vertical bipolar battery cells to achieve connection, and can also ensure the insulation between the two adjacent vertical bipolar battery cells. The present application adopts an internal parallel vertical structure, which has a higher capacity and voltage, and can also maintain a higher energy density compared to external parallel. The structure of the present application can effectively simplify the manufacturing process of bipolar batteries. The present application has a simple structure, greatly reduces the difficulty of sealing, has a low cost, can be manufactured using existing equipment, and is easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 1 is a schematic cross-sectional view of a vertical bipolar battery structure according to an embodiment of the present invention;

[0020] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure of a vertical bipolar battery cell;

[0021] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure of the end face bipolar pole piece;

[0022] Figure 4 yes Figure 3 Schematic diagram of the front (A) and back (B) of the composite current collector;

[0023] Figure 5 yes Figure 2 A schematic diagram of the front view structure of the connected bipolar pole pieces;

[0024] Figure 6 yes Figure 5 A schematic diagram of the cross-sectional structure of the connected bipolar pole pieces;

[0025] Figure 7 yes Figure 2 A schematic diagram of the front view structure of the bipolar pole piece;

[0026] Figure 8 yes Figure 2 Schematic diagram of the cross-sectional structure of the bipolar pole piece. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0028] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, top, bottom...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0029] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0030] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.

[0031] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0032] Specifically, such as Figures 1 to 2 As shown, an embodiment of the present invention provides a vertical bipolar battery structure, comprising at least two stacked vertical bipolar battery cell units 100; each of the vertical bipolar battery cell units 100 comprises an end bipolar pole piece 10, at least one bipolar pole piece 20 and a connecting bipolar pole piece 30, the end bipolar pole piece 10, the bipolar pole piece 20 and the connecting bipolar pole piece 30 are stacked in sequence, and a diaphragm 40 is provided between the end bipolar pole piece 10 and the bipolar pole piece 20, and between the bipolar pole piece 20 and the connecting bipolar pole piece 30; two adjacent vertical bipolar battery cell units 100 share the connecting bipolar pole piece 30.

[0033] As a preferred embodiment, two adjacent vertical bipolar battery cell units 100 are connected in parallel; in the same vertical bipolar battery cell unit 100, the end face bipolar pole piece 10, the bipolar pole piece 20 and the connecting bipolar pole piece 30 are sequentially connected in series.

[0034] In this embodiment, three vertical bipolar battery cell units 100 are provided. The vertical bipolar battery cell unit 100 provided in the middle is connected to one of the vertical bipolar battery cell units 100 via an end bipolar pole piece, and is connected to another vertical bipolar battery cell unit 100 via a connecting bipolar pole piece. Each vertical bipolar battery cell unit 100 includes an end bipolar pole piece 10, two bipolar pole pieces 20, and a connecting bipolar pole piece 30. The bipolar pole piece 10, bipolar pole piece 20, bipolar pole piece 20, and connecting bipolar pole piece 30 are stacked in the order of bipolar pole piece 10, bipolar pole piece 20, bipolar pole piece 20, and connecting bipolar pole piece 30.

[0035] As a preferred embodiment, the end bipolar pole piece 10 and the connecting bipolar pole piece 30 have the same structure and size. In this application, the end bipolar pole piece and the connecting bipolar pole piece have the same structure; in this way, when a plurality of (such as) vertical bipolar battery structures are provided, Figure 1 When three vertical bipolar battery cell units 100 are shown, the vertical bipolar battery cell unit 100 arranged in the middle is connected to one of the adjacent vertical bipolar battery cell units 100 through the end bipolar pole piece, and is connected to another adjacent vertical bipolar battery cell unit 100 through the connecting bipolar pole piece.

[0036] As a preferred embodiment, Figures 3 and 4 As shown, the end face bipolar pole piece 10 includes a first composite current collector 11, a first positive electrode coating 12 arranged on one side of the first composite current collector 11, and a first negative electrode coating 13 arranged on the other side of the first composite current collector 11; the area of ​​the first negative electrode coating 13 is larger than the area of ​​the first positive electrode coating 12, and the center of the first negative electrode coating 13 overlaps with the center of the first positive electrode coating 12.

[0037] As a preferred embodiment, Figure 4As shown, the first composite current collector 11 includes a first insulating material 111, a first current collector 112 disposed on one side of the first insulating material 111, and a second current collector 113 disposed on the other side of the first insulating material 111. In a direction perpendicular to the first insulating material 111, the first current collector 112 and the second current collector 113 are staggered. The first negative electrode coating 13 is disposed on the side of the first current collector 112 away from the first insulating material 111. The first positive electrode coating 12 is disposed on the side of the second current collector 113 away from the first insulating material 111. That is, in a direction perpendicular to the first insulating material 111, the first current collector 112 and the second current collector 113 are not completely overlapped, but are staggered. The lead tab area of ​​the first current collector 112 is composed of only one side of the first current collector 112 and the first insulating material 111, while the lead tab area of ​​the second current collector 113 is composed of only one side of the second current collector 113 and the first insulating material 111. This facilitates the connection and arrangement of battery cells and helps save space.

[0038] As a preferred embodiment, Figures 5 and 6 As shown, the connected bipolar pole piece 30 includes a second composite current collector 31, a second positive electrode coating 32 arranged on one side of the second composite current collector 31, and a second negative electrode coating 33 arranged on the other side of the second composite current collector 31; the area of ​​the second negative electrode coating 33 is larger than the area of ​​the second positive electrode coating 32, and the center of the second negative electrode coating 33 overlaps with the center of the second positive electrode coating 32.

[0039] As a preferred embodiment, the second composite current collector 31 includes a second insulating material 311, a third current collector 312 disposed on one side of the second insulating material 311, and a fourth current collector 313 disposed on the other side of the second insulating material 311. The third current collector 312 and the fourth current collector 313 are staggered in a direction perpendicular to the second insulating material 311. The second negative electrode coating 33 is disposed on the side of the third current collector 312 away from the second insulating material 311. The second positive electrode coating 32 is disposed on the side of the fourth current collector 313 away from the second insulating material 311. That is, in a direction perpendicular to the second insulating material 311, the third current collector 312 and the fourth current collector 313 are not completely overlapped but are staggered. The lead tab area of ​​the third current collector 312 is composed of only one side of the third current collector 312 and the second insulating material 311, while the lead tab area of ​​the fourth current collector 313 is composed of only one side of the fourth current collector 313 and the second insulating material 311. This facilitates connection and arrangement between battery cells and helps save space.

[0040] As a preferred embodiment, Figures 7 and 8 As shown, the bipolar pole piece 20 includes a fifth current collector 21, a third positive electrode coating 22 arranged on one side of the fifth current collector 21, and a third negative electrode coating 23 arranged on the other side of the fifth current collector 21; the area of ​​the third negative electrode coating 23 is larger than the area of ​​the third positive electrode coating 22, and the center of the third negative electrode coating 23 overlaps with the center of the third positive electrode coating 22.

[0041] As a preferred embodiment, the first negative electrode coating 13 , the second negative electrode coating 33 and the third negative electrode coating 23 have the same area; the first positive electrode coating 12 , the second positive electrode coating 32 and the third positive electrode coating 22 have the same area.

[0042] As a preferred embodiment, a sealed insulating layer 50 is provided between the first current collector 112 and the diaphragm 40, between the second current collector 113 and the diaphragm 40, between the third current collector 312 and the diaphragm 40, between the fourth current collector 313 and the diaphragm 40, and between the fifth current collector 21 and the diaphragm 40. The sealed insulating layer 50 can lock the electrolyte between the positive and negative electrodes to prevent the liquid electrolyte from leaking, allowing the structure of the present application to use a liquid electrolyte as the electrolyte; using a liquid electrolyte as the electrolyte ensures low interfacial impedance and high ionic conductivity.

[0043] As a preferred embodiment, the first negative electrode coating 13, the second negative electrode coating 33, and the third negative electrode coating 23 are all disposed in contact with the corresponding sealing insulating layer 50; and gaps 60 are provided between the first positive electrode coating 12, the second positive electrode coating 32, and the third positive electrode coating 22 and the corresponding sealing insulating layer 50. In this application, the sealing insulating layer is generally fixed by point hot melt adhesive to facilitate subsequent lamination and sealing.

[0044] The sealing insulating layer, the first insulating material and the second insulating material can be made of thermosetting materials with good electrolyte tolerance, such as polypropylene and polyethylene. The diaphragm can also be made of porous thermosetting materials with good electrolyte tolerance.

[0045] The vertical bipolar battery structure of the present application may be a secondary battery structure such as a potassium ion battery structure, a lithium ion battery structure or a calcium ion battery structure.

[0046] In the structure of the present application, the end bipolar pole piece and the connecting bipolar pole piece adopt the same structure, which effectively simplifies the types of pole pieces of the present application, so that the structure of the present application can be realized by using two pole piece structures. The structure of the present application has fewer types of electrode pieces when stacking, is less complex, and is convenient for mechanized mass production; by stacking two pole pieces in a simple way to form a vertical bipolar battery cell unit, and superimposing this unit inside the battery, the voltage and capacity of the single cell are improved. In addition, the interior of the battery cell is sealed by a sealed insulating layer, so that the structure of the present application can use a liquid electrolyte as the electrolyte, which has better conductivity than solid electrolytes and gel electrolytes.

[0047] When stacking, place the end bipolar pole pieces (including the connected bipolar pole pieces) and the bipolar pole pieces in two loading areas respectively, with the positive poles of all pole pieces facing upwards and the negative poles facing downwards (or the positive poles facing downwards and the negative poles facing upwards). The current collector direction of the exposed tabs of the pole pieces must also be consistent. Figure 2 As shown, the number of bipolar pole pieces in each vertical bipolar battery cell unit is X (X is at least 1), and the pole pieces are separated by diaphragms and stacked in a Z-shape.

[0048] When sealing, the sealing insulation layer is heated and sealed, and the diaphragm can also be fused, leaving one side unsealed and fused as the liquid injection port. At the same time, the positive and negative pole ears leading out of the bipolar pole piece on the end face are welded (make sure that the sealing material at the ear is melted so that the ear is completely welded together). After the liquid is injected, the reserved liquid injection port can be heat-sealed.

[0049] Throughout this specification, references to terms such as "one embodiment" and "example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example.

[0050] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A vertical bipolar battery structure, characterized in that: It comprises at least two stacked vertical bipolar battery cell units; each of the vertical bipolar battery cell units comprises an end bipolar pole piece, at least one bipolar pole piece and a connecting bipolar pole piece, the end bipolar pole piece, the bipolar pole piece and the connecting bipolar pole piece are stacked in sequence, and a diaphragm is provided between the end bipolar pole piece and the bipolar pole piece, and between the bipolar pole piece and the connecting bipolar pole piece; two adjacent vertical bipolar battery cell units share the connecting bipolar pole piece.

2. The vertical bipolar battery structure according to claim 1, characterized in that: Two adjacent vertical bipolar battery cell units are connected in parallel; in the same vertical bipolar battery cell unit, the end face bipolar pole piece, the bipolar pole piece and the connecting bipolar pole piece are sequentially connected in series.

3. The vertical bipolar battery structure according to claim 1, characterized in that: The end bipolar pole piece and the connecting bipolar pole piece have the same structure and size.

4. The vertical bipolar battery structure according to claim 1, characterized in that: The end face bipolar pole piece includes a first composite current collector, a first positive electrode coating arranged on one side of the first composite current collector, and a first negative electrode coating arranged on the other side of the first composite current collector; the area of ​​the first negative electrode coating is larger than the area of ​​the first positive electrode coating, and the center of the first negative electrode coating overlaps with the center of the first positive electrode coating.

5. The vertical bipolar battery structure according to claim 4, characterized in that: The first composite current collector includes a first insulating material, a first current collector arranged on one side of the first insulating material, and a second current collector arranged on the other side of the first insulating material; in a direction perpendicular to the first insulating material, the first current collector and the second current collector are staggered; the first negative electrode coating is arranged on the side of the first current collector away from the first insulating material; the first positive electrode coating is arranged on the side of the second current collector away from the first insulating material.

6. The vertical bipolar battery structure according to claim 5, characterized in that: The connected bipolar pole piece includes a second composite current collector, a second positive electrode coating arranged on one side of the second composite current collector, and a second negative electrode coating arranged on the other side of the second composite current collector; the area of ​​the second negative electrode coating is larger than the area of ​​the second positive electrode coating, and the center of the second negative electrode coating overlaps with the center of the second positive electrode coating.

7. The vertical bipolar battery structure according to claim 6, characterized in that: The second composite current collector includes a second insulating material, a third current collector arranged on one side of the second insulating material, and a fourth current collector arranged on the other side of the second insulating material; in a direction perpendicular to the second insulating material, the third current collector and the fourth current collector are staggered; the second negative electrode coating is arranged on the side of the third current collector away from the second insulating material; the second positive electrode coating is arranged on the side of the fourth current collector away from the second insulating material.

8. The vertical bipolar battery structure according to claim 7, characterized in that: The bipolar pole piece includes a fifth current collector, a third positive electrode coating arranged on one side of the fifth current collector, and a third negative electrode coating arranged on the other side of the fifth current collector; the area of ​​the third negative electrode coating is larger than the area of ​​the third positive electrode coating, and the center of the third negative electrode coating overlaps with the center of the third positive electrode coating.

9. The vertical bipolar battery structure according to claim 8, characterized in that: The first negative electrode coating, the second negative electrode coating and the third negative electrode coating have the same area; the first positive electrode coating, the second positive electrode coating and the third positive electrode coating have the same area.

10. The vertical bipolar battery structure according to claim 8, characterized in that: A sealing insulating layer is provided between the first current collector and the diaphragm, between the second current collector and the diaphragm, between the third current collector and the diaphragm, between the fourth current collector and the diaphragm, and between the fifth current collector and the diaphragm; The first negative electrode coating, the second negative electrode coating and the third negative electrode coating are all arranged in contact with the corresponding sealing insulating layer; and gaps are set between the first positive electrode coating, the second positive electrode coating and the third positive electrode coating and the corresponding sealing insulating layer.

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